1. Field of the Invention
The present invention relates generally to the field of stem cell differentiation. More particularly, it concerns a method for developing natural killer cells that can be used in killing cancerous cells and/or virally-infected cells.
2. Description of Related Art
Natural killer cells (NK) cells are cytotoxic lymphocytes and play a role in an innate immune system. For example, NK cells can respond to virally infected cells and tumors. NK cells also play a role in adaptive immune response. Generally, NK cells differentiate and mature in the bone marrow, lymph node, spleen, tonsils, and thymus.
Pluripotent stem cells can differentiate into diverse specialized cell types including all derivatives of the three primary germ layers: ectoderm, endoderm, and mesoderm. Human embryonic stem cells (hESCs) are pluripotent stem cells derived from the inner cell mass of the blastocyst, an early-stage human embryo. Induced pluripotent stem cells (iPSCs) are a type of pluripotent stem cell artificially derived from a non-pluripotent cell (typically an adult somatic cell) by expression of specific genes. The process of lymphopoiesis initiating from hematopoietic cell populations isolated from mouse or human bone marrow or human umbilical cord blood (UCB) has been documented, but relatively little is known about the ability of undifferentiated hESCs or iPSCs to differentiate into the lymphoid lineage.